The invention relates to telecommunication switching systems and, in particular, to a unified access switch digit translation system for providing digit translation and call routing in a telecommunication system.
Telecommunication carriers are increasingly deploying multi-service packages, or bundled services, to customers to provide reduced overall access charges in an attempt to increase customer retention. For example, the boom in digital subscriber line subscriptions has led many carriers to bundle high bandwidth Internet service with traditional voice services. The carrier can advantageously charge a higher fee for the bundled service than the individual service fees of any of the services that are bundled together while still offering a bundled service fee less than the sum of typical fees of the individual services thus providing an incentive for customers to subscribe to additional services. Recent market trends indicate an extensive consumer demand for these bundled services. Numerous cable carriers also provide bundled services in the form of traditional pay cable television services bundled with high bandwidth cable Internet access. Deregulation in the telecommunication industry that is now allowing long distance carriers to compete with local carriers promises to bring additional bundled services to the consumer. Wireless services are also being bundled with numerous combinations of the abovementioned services. Market trends with regard to bundled services are unmistakable. Successful carriers of the future will have the ability to offer various packages of voice and data services. Already, carriers are feeling the strain of successfully upgrading existing infrastructures to meet the high-bandwidth services being demanded by customers. Some local carriers are currently reporting up to three year back logs of orders for DSL services, for example.
Transition networks are commonly utilized to provide customer access to voice and data networks. An access network interfaces with voice and data switches each respectively interfacing with a data network, for example a packet backbone network, and the public switched telephone network. Typically, various classes of voice switches, for example class 4 switches for providing interexchange carrier (IXC) voice services and class 5 switches for providing end office voice services, are required within the transition network. Multiple media gateways are then required to interface with a data access switch. However, work towards a truly integrated voice and data network is underway.
Significant amounts of labor are expended to maintenance and upgrade the transition networks as new services become available. A move to unified access is clearly advantageous and promises to propel emerging technologies that are not easily implemented over current large scale networks, for example voice over IP (VoIP) and voice over DSL (VoDSL), to a broader degree of acceptance.
Unified access will require greatly improved switching systems that are commonly found in the PSTN today. The switching fabric will require various services to be switched to numerous other disparate networks. For example, a inbound time division multiplex message would need to be able to be switched to another time division multiple channel as well as various other networks, for example IP for a terminating VoIP customer. Similarly, the unified switch would need to be capable of switching an IP originating call to an IP, TDM, frame relay and ATM network, to name just a few. Clearly, a switch required to realize unified access will have sophistication not embodied in typical switches found in carrier networks today.
Typically, digit translation performed in telecommunication switching systems is limited in the amount of servicing provided for data networks. A unified access switch would preferably be capable of handling translation for all calls being translated and routed therefrom. Furthermore, in today""s switching systems, the lookup tables (referred to hereinafter simply as xe2x80x98tablexe2x80x99) generally have records for each termination type capable of being routed from the switch. By integrating data services into a unified access switch, the size of these tables will undoubtedly grow as services, for example screening services, now common with many voice services become deployed for data services.
In accordance with an embodiment of the present invention, an optimal digit translation and call processing system and method is provided that reduces the size of the tables required for performing digit translation. A prefix translation and digit characterization process are performed utilizing a digit prefix table and a second table interfaced therewith. The digit prefix table contains numerous records corresponding to prefixes of dialed digit streams. Each record includes an index to a record of a second table operable to output a termination type of the digit stream. The second table includes numerous records associated with various call termination types. Each index included within respective records of the digit prefix table may reference more than one record of the second table. The digit stream length is analyzed to resolve ambiguities in the digit stream when an index in a record of the digit prefix table references more than one record of the second table. Multiple records of the digit prefix table may have a common index to an identical record of the second table thus reducing the required number of records in the second table for characterizing call termination types. In accordance with another embodiment of the present invention, a call screening table is interrogated with termination type data obtained from the second table. The call screening table can pass call control to a national or international translator table which provide a route index on which further call processing is performed. The route index may be modified by an originator routing table, a carrier identification code routing table and a time of day routing table before the call is ultimately routed.